This invention relates to multiple-tier databases, including but not limited to updating of multiple-tier mobility databases in radio frequency (RF) communication systems.
Many types of systems use multiple tier databases to more efficiently be able to use stored data without overburdening a single repository of the data. Information in such a database may be entered or updated at any tier of the database and then communicated between the various tiers to ensure that the latest data is provided to all tiers requiring such data.
The basic operation and structure of a land mobile communication unit system is well known. Land mobile communication unit systems typically comprise one or more communication units (e.g., vehicle-mounted or portable communication units in a land mobile system and communication unit/telephones in a cellular system) and one or more repeaters that transceive information via the RF communication resources. These communication resources may be narrow band frequency modulated channels, time division multiplex slots, frequency pairs, and so forth. Land mobile communication unit systems may be organized as trunked communication systems, where a plurality of communication resources is allocated amongst a group of users by assigning the repeaters on a communication-by-communication basis within an RF coverage area.
In a typical communications network, a subscriber, or user, database is maintained that includes user information, user profiles, feature activation status, access privileges, and so forth. This database is typically referred to as a home location register (HLR), and is well understood. Upon receiving a request for registration from a communication unit, the network equipment accesses the HLR, finds the correlating subscriber record, and determines what features to activate for the communication unit, as well as the necessary authentication information, among other pertinent information. This information is transferred to another database called the visitors location register (VLR), which is also well understood in the art. The VLR is used by the system to also track the communication unit""s location in the system, i.e., what particular cell or cells the communication unit was most recently in, so that an incoming call may be routed.
The HLR and VLR may be constructed as a multiple-tier database, which may be referred to as a mobility database. Typically, when the VLR is updated with information, the VLR immediately passes the updated information to the HLR. In certain circumstances, it may be necessary to update large amounts of data between the various tiers of such a database. In these situations, immediately passing the data between the various tiers may send data at such a rate that one or more tiers of the database are unable to keep up with the amount of data being transferred, thereby resulting in data not being entered, data buffers being over run, and even one or more components of the database crashing, thereby compounding the problem.
Accordingly, there is a need for a method of updating a multiple tier database that avoids over-running any of the components of the database.